Fluidic system for performing assays

ABSTRACT

A fluidic testing system and method for use are presented. The fluidic testing system includes a microfluidic channel, a first chamber and second chamber. The microfluidic channel has only one port for the introduction and/or extraction of fluid through the microfluidic channel. The first chamber is disposed at a terminal end of the microfluidic channel. The second chamber is coupled to the fluidic channel and is aligned such that each opening to the second chamber is configured to be aligned substantially parallel to a gravity vector during operation.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.15/210,734, filed on Jul. 14, 2016, which claims the benefit of U.S.provisional application No. 62/193,884, filed on Jul. 17, 2015, whichare incorporated herein in their entireties by reference.

BACKGROUND Field

Embodiments of the present invention relate to the field of clinicaldiagnostic tools.

Background

Given the complexity of the automation of molecular testing andimmunoassay techniques, there is a lack of products that provideadequate performances to be clinically usable in near patient testingsettings. Typical molecular testing includes various processes involvingthe correct dosage of reagents, sample introduction, lysis of cells toextract DNA or RNA, purification steps, and amplification for itssubsequent detection. Even though there are central laboratory roboticplatforms that automate some of these processes, for many testsrequiring a short turnaround time, the central laboratory cannot providethe results in the needed time requirements.

However, it is difficult to implement systems in a clinical setting thatprovide accurate, trustworthy results at a reasonable expense. Given thecomplicated nature of various molecular testing techniques, the resultsare prone to error if the testing parameters are not carefullycontrolled or if the environmental conditions are not ideal.

The fact that molecular techniques have exceptional sensitivity levelsat concentrations lower than the previous reference methods makes itrather difficult to obtain clinically relevant conclusions, whileavoiding erroneous calls with false positives. To minimize this problem,especially for the detection of pathogen microorganisms, tests shouldhave quantification capability. It has therefore become increasinglynecessary to perform multiplexed assays and arrays of tests toconsolidate enough data to make confident conclusions. While techniquessuch as microarray immunoassays provide very high multiplexing capacity,their main limitation is the low speed in obtaining the results, whichoften have no positive impact on patient management.

SUMMARY

A fluidic testing system and method of use are presented. Simultaneousfluid control of each testing site can reduce testing time and enhancethe probability of obtaining repeatable results among the varioustesting sites.

In an embodiment, a fluidic testing system includes a microfluidicchannel, a first chamber and a second chamber. The microfluidic channelhas only one port for the introduction and/or extraction of fluidthrough the microfluidic channel. The first chamber is disposed at aterminal end of the microfluidic channel. The second chamber is coupledto the fluidic channel and is aligned such that each opening to thesecond chamber is configured to be aligned substantially parallel to agravity vector during operation.

An example method is described. The method includes flowing a liquidthrough the only port of a microfluidic channel until the liquid reachesone or more reagents stored in a first chamber coupled to themicrofluidic channel. Afterwards, the method includes re-suspending atleast a portion of the one or more reagents within the liquid to form atarget liquid. The target liquid is then flown through the microfluidicchannel and away from the first chamber. The method then includesflowing the target liquid back and forth within the microfluidicchannel, such that the target liquid flows through a second chambercoupled to the microfluidic channel. The method includes reacting atleast a portion of the one or more re-suspended reagents within thetarget liquid with one or more reagents disposed within the secondchamber and flowing the target liquid out of the microfluidic channelvia the only port of the microfluidic channel.

In another embodiment, a fluidic testing system includes a microfluidicchannel, a plurality of chambers, and a chamber disposed at a terminalend of the microfluidic channel. The microfluidic channel has only oneport for the introduction and/or extraction of fluid through themicrofluidic channel. Each of the plurality of chambers is coupled tothe microfluidic channel in a series arrangement, such that a length ofeach of the plurality of chambers is aligned substantially parallel to agravity vector.

BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES

The accompanying drawings, which are incorporated herein and form a partof the specification, illustrate embodiments of the present inventionand, together with the description, further serve to explain theprinciples of the invention and to enable a person skilled in thepertinent art to make and use the invention.

FIG. 1A is a graphical representation of a test cartridge system,according to an embodiment.

FIG. 1B displays another view of the test cartridge system, according toan embodiment.

FIG. 2 illustrates a fluidic testing arrangement, according to anembodiment.

FIG. 3 illustrates a plurality of fluidic testing arrangements,according to an embodiment.

FIGS. 4A-4B illustrate views of a fluidic testing arrangement, accordingto some embodiments.

FIG. 5 illustrates another fluidic testing arrangement, according to anembodiment.

FIG. 6 illustrates an example fluidic testing method, according to anembodiment.

Embodiments of the present invention will be described with reference tothe accompanying drawings. DETAILED DESCRIPTION

Although specific configurations and arrangements are discussed, itshould be understood that this is done for illustrative purposes only. Aperson skilled in the pertinent art will recognize that otherconfigurations and arrangements can be used without departing from thespirit and scope of the present invention. It will be apparent to aperson skilled in the pertinent art that this invention can also beemployed in a variety of other applications.

It is noted that references in the specification to “one embodiment,”“an embodiment,” “an example embodiment,” etc., indicate that theembodiment described may include a particular feature, structure, orcharacteristic, but every embodiment may not necessarily include theparticular feature, structure, or characteristic. Moreover, such phrasesdo not necessarily refer to the same embodiment. Further, when aparticular feature, structure or characteristic is described inconnection with an embodiment, it would be within the knowledge of oneskilled in the art to effect such feature, structure or characteristicin connection with other embodiments whether or not explicitlydescribed.

Some embodiments described herein relate to a microfluidic arrangementintegrated within a test cartridge system for performing a variety ofmolecular tests, such as immunoassays, PCR, DNA hybridization, etc. Inan embodiment, the test cartridge integrates all of the componentsnecessary to perform such tests into a single, disposable package. Thetest cartridge may be configured to be analyzed by an externalmeasurement system which provides data related to the reactions thattake place within the test cartridge. In an embodiment, the testcartridge includes a plurality of testing chambers with a transparentwindow to perform optical detection with each testing chamber.

In one example, a single test cartridge may be used to perform an arrayof immunoassays with a given sample. The test cartridge contains all ofthe necessary buffers, reagents, and labels held in sealed chambersintegrated into the cartridge to perform the immunoassays.

One of the main limitations of molecular diagnostic instrumentation isthe problem associated with contamination such as cross-contamination,carry-over contamination, etc. Embodiments described hereinsubstantially eliminate by design the contamination of samples to theinstrument.

In one embodiment, the test cartridge offers a self-contained liquid ordried reagents sealed during the manufacturing process. The reagents andthe introduced sample do not enter into contact with the environment orwith any part of the instrument. This feature of the test cartridge isalso important for many laboratories and hospitals to safely dispose ofthe products after their use.

In order to perform an array of tests, the test cartridge contains aplurality of testing chambers as well as a plurality of fluidicchannels. The fluidic channels may be designed to connect the varioustesting chambers together, and transfer liquid to other portions of thetest cartridge. The fluidic channels may be designed to facilitateperforming immunoassays within connected chambers along the fluidicchannels.

Some details relating to the components of the test cartridge system aredescribed herein with references made to the figures. It should beunderstood that the illustrations of each physical component are notmeant to be limiting and that a person having skill in the relevantart(s) given the description herein would recognize ways to re-arrangeor otherwise alter any of the components without deviating from thescope or spirit of the invention. A more detailed explanation of thetest cartridge system may be found in co-pending U.S. application Ser.No. 13/836,845, the disclosure of which is incorporated by referenceherein in its entirety.

FIG. 1A illustrates an example test cartridge system 100, according toan embodiment. Test cartridge system 100 includes a cartridge housing102, which may house a variety of fluidic chambers, channels, andreservoirs. Samples may be introduced into cartridge housing 102 viasample port 104, according to an embodiment. In an example, sample port104 receives solid, semi-solid, or liquid samples. Sample port 104 mayalso be designed to receive a needle of a syringe in order to inject asample into a chamber or fluidic channel within cartridge housing 102.In another embodiment, cartridge housing 102 includes more than oneinlet to introduce samples. Further details about the various chambersand channels of cartridge system 100 may be found in co-pending U.S.application Ser. No. 13/836,845.

According to an embodiment, cartridge system 100 may include a transferchamber that moves laterally along a guide 106 within cartridge housing102. This transfer chamber may be used to align various fluid ports withthe transfer chamber and control movement of the fluid throughout thevarious fluidic channels and chambers of cartridge system 100.

Cartridge system 100 includes one or more through-holes 108 according toan embodiment. Through-holes 108 may be located on a thinner portion ofcartridge system 100. In one example, this thinner portion is locatedaway from many of the fluid chambers within cartridge housing 102.Through-holes 108 allow for various reagents to be placed withinthrough-holes 108, effectively “plugging” the holes. As such, thereagents may be disposed upon small plugs that fit snugly withinthrough-holes 108. Examples of reagents may include immobilizedantibodies, proteins, enzymes, and single-stranded or double-strandedDNA or RNA. A gasket seal may be used around the edges of the plug toensure a substantially leak-proof fit. Further details of these plugsare described below with reference to FIG. 4.

FIG. 1B illustrates a view of a backside of the example test cartridgesystem 100, according to an embodiment. Numerous fluidic channels can beseen within cartridge housing 102. In one example, these fluidicchannels are microfluidic channels, where the fluid flow through thechannels is in the laminar flow regime. As such, the dimensions of themicrofluidic channels may have cross sections less than, for example, 5mm², less than 1 mm², less than 10,000 μm², less than 5,000 μm², lessthan 1,000 μm², or less than 500 μm².

According to an embodiment, various fluidic testing areas areincorporated within cartridge housing 102. For example, a testing area110 may include a plurality of fluidic testing arrangements, each havingan opening 112 that is aligned with one of the through-holes 108 fromthe other side of test cartridge 100. As such, each of openings 112,when plugged with reagents, defines a testing chamber for variousbiological and chemical tests. These tests may involve immunoassays,enzyme interactions, cellular responses, or DNA hybridization, just toname a few. Other tests to be performed would be apparent to one ofordinary skill in the art given the disclosure herein. Further detailsregarding each of the testing arrangements illustrated in testing area110 are described below with reference to FIG. 2.

Another fluidic area 114 includes a plurality of chambers connected in aseries arrangement, according to an embodiment. These chambers may beused for dilutions and to provide accurate dosing concentrations toother chambers and fluidic channels within the system. Further detailsregarding the illustrated fluidic area 114 are described below withreference to FIG. 5. Other various fluidic channels 116 are shown aswell and may be used to guide fluid between various chambers withincartridge housing 102, and fluid to/from the various chambers to any ofthe channels shown in testing area 110 or fluidic area 114.

FIG. 2 illustrates an example of a fluidic testing arrangement 200,according to an embodiment. A gravity vector is also shown to providethe orientation that fluidic testing arrangement 200 is designed to beused for maximum effectiveness, according to one example. Otherorientations may be possible as well, although the other orientationsmay cause unwanted air bubbles to form within the channels.

Fluidic testing arrangement 200 includes a microfluidic channel 202having only one port 204, according to an embodiment. The other end ofmicrofluidic channel 202 terminates at a closed chamber 216. This closedchamber acts as a reservoir for the air that is trapped withinmicrofluidic channel 202 as fluid is pushed through microfluidic channel202 via port 204. The inclusion of closed chamber 216 replaces the needfor using a vent to allow the air to escape the system. Not having avent provides advantages such as reducing the probability of leakage andcontamination.

Microfluidic channel 202 may have one or more chambers or enlarged areasdisposed along a length of microfluidic channel 202. For example,microfluidic channel 202 may include one or more channel enlargements206, such as 206 a and 206 b. Channel enlargements 206 a and 206 b mayact as liquid sensing areas. As such, channel enlargements 206 a and 206b may be used along with one or more external optical probes todetermine whether or not liquid is present within channel enlargements206 a and 206 b. This determination may be used to activate otherfunctions of test cartridge system 100. In another embodiment, channelenlargements 206 a and 206 b may include integrated sensors, such as apatterned resistive sensor, to indicate the presence or flow rate of thefluid.

Microfluidic channel 202 may also be coupled with a mixing chamber 208.In an embodiment, mixing chamber 208 has a larger cross-sectionaldimension than the microfluidic channel 202. This larger cross sectionaldimension may be chosen such that the fluid regime within mixing chamber208 is no longer laminar, but turbulent. By varying the pressure appliedto port 204, a sample solution may be moved back and forth within mixingchamber 208, thus providing a passive mixing of the fluid. According toan embodiment, mixing chamber 208 is aligned such that the openings tomixing chamber 208 are substantially aligned with the gravity vector.This alignment helps to reduce the creation of air bubbles within thechamber as the fluid is being mixed.

Microfluidic channel 202 also includes a testing chamber 210. In oneexample, testing chamber 210 is located further downstream than mixingchamber 208 within microfluidic channel 202. Testing chamber 210 may bealigned over one of the through-holes 108 illustrated in FIG. 1A. Assuch, reagents may be placed into testing chamber 210 by “plugging” oneside of testing chamber 210, using a plug insert as illustrated in FIG.4. The geometry of testing chamber 210 allows for a large surface areafor interaction with various reagents in testing chamber 210. Forexample, the diameter of testing chamber 210 may be chosen to besubstantially similar to that of a single plate of a standard-sized96-well plate, 24-well plate, 48-well plate, or 384-well plate. Thefluid volume within testing chamber 210 may be less than 50 μL. In oneexample, the fluid volume within testing chamber 210 is between 10 and30 μL. The volume of testing chamber 210 may be designed large enough tobe completely filled by a 50 μL sample solution. In an embodiment, theopenings of testing chamber 210 are aligned substantially parallel tothe gravity vector. With the openings aligned in this way, the chambermay be placed along fluidic channel such that fluid can fill the chamberfrom the bottom-up. By filling testing chamber 210 in this way, thegeneration of air bubbles may be reduced. In one embodiment, testingchamber 210 may include a plurality of beads to increase the surfacearea for reagent interaction. By varying the pressure applied to port204, the sample solution may be moved back and forth within testingchamber 210, to maximize the interaction between the reagentsimmobilized within testing chamber 210 and the reagents within thesample solution.

The larger cross sectional dimension of testing chamber 210 may bechosen such that the fluid regime within testing chamber 210 is nolonger laminar, but turbulent. This turbulent flow increases thereaction kinetics between immobilized reagents in testing chamber 210and reagents within the solution. According to an embodiment, testingchamber 210 is aligned such that the openings to testing chamber 210 aresubstantially aligned with the gravity vector. This alignment helps toreduce the creation of air bubbles within the chamber as the samplesolution is moved back and forth in testing chamber 210.

Detection of reagent interactions within testing chamber 210 may occurusing an external optical source and photodetector coupled to ananalyzer in which test cartridge system 100 is placed. Thus, any wallsor covers of testing chamber 210 may be transparent to allow for opticaldetection. In one example, the photodetector measures absorbance throughthe liquid within testing chamber 210 at one or more wavelengths. Inanother example, the photodetector measures a fluorescence signalgenerated from a fluorescent compound within testing chamber 210. In anembodiment, the fluorescence measurements are taken from beneath testingchamber 210. Testing chamber 210 may be adapted for other means ofdetection, e.g., electrochemical, electromechanical, surface plasmonresonance, time-resolved fluorescence, etc.

A storage chamber 212 may be located along microfluidic channel 202 andfurther downstream of testing chamber 210. Storage chamber 212 mayinclude dry chemicals, such as frozen or lyophilized analytes. Inanother example, storage chamber 212 includes dry reagents 214 orbiological samples. The biological samples may be freeze dried withinstorage chamber 212. Such biological or chemical compounds may be storedin storage chamber 212 for long periods of time before use. Thedimensions of storage chamber 212 may be designed to specifically fitthe size of dried reagents 214 (such as a dried chemistry bead), usuallyon the order of a few millimeters in diameter, according to oneembodiment. In one example, fluid drawn towards storage chamber 212mixes with and re-suspends the dried reagents 214 within the fluid. Theliquid having the resuspended reagents may then be drawn back towardstesting chamber 210 for analysis.

The various chambers along microfluidic channel 202 may be strategicallyplaced depending on the application and test being performed. Forexample, in the arrangement illustrated in FIG. 2, a buffer liquid maybe forced, via an applied positive pressure, through port 204 and allthe way around to storage chamber 212 to re-suspend the dried reagents214 within the buffer solution to form a test solution. Next, the testsolution may be drawn back through microfluidic channel 202, via anegative pressure applied at port 204, or by releasing the positivepressure applied previously. The test solution may be brought back allthe way to channel enlargement 206 a. After this, the fluid may beforced back and forth between channel enlargement 206 a and storagechamber 212 multiple times, passing through both mixing chamber 208 andtesting chamber 210. In this way, the fluid continues to be mixed viamixing chamber 208 while interacting with the captured reagents withintesting chamber 210. In the example of an immunoassay, captureantibodies are immobilized within testing chamber 210 while proteinspresent within the test solution are introduced to the captureantibodies. A binding reaction may indicate a positive test result (andproduce a florescent signal). Once the test solution has been introducedenough times through testing chamber 210, it may be drawn out of port204, and a different wash solution may be introduced to wash away anyunbound material within testing chamber 210 (e.g., in an effort toeliminate false positives). The wash solution can be introduced over theanalytes within testing chamber 210 without having to pass throughstorage chamber 212. This is advantageous as it avoids possiblere-suspension of any of the dry chemicals left in storage chamber 212.It should be understood that this is just one example use of fluidictesting arrangement 200, and that the arrangement of chambers may bechanged based on the application.

FIG. 3 illustrates a plurality of fluidic testing arrangements connectedto the same input fluidic channel 302, according to an embodiment. Inputfluidic channel 302 includes a single port 304 for the introduction andexpulsion of liquid, and for applying, or releasing, pressure to theliquid. Input fluidic channel 302 may be coupled to a fluidic junction306 where a single fluidic channel splits into a plurality of fluidicchannels. In one example, each of the plurality of fluidic channelsfeeds its own testing arrangement 308. Although only three testingarrangements 308 are illustrated as connected to input fluidic channel302, it should be understood that any number and type of fluidic testingarrangements may be coupled to input fluidic channel 302.

Storage chamber 310 within each testing arrangement 308 may include adifferent concentration of reagents or different reagents altogetherfrom other storage chambers 310. Similarly, the reagents placed withintesting chamber 312 within each testing arrangement 308 may include adifferent concentration of reagents or different reagents altogetherfrom other testing chambers 312. In this way, a multiplexed array ofexperiments may be performed from the same input fluidic channel 302.

FIGS. 4A and 4B illustrate a procedure for placing a reagent insert 402within a testing chamber 210 that is part of a fluidic testingarrangement 200, according to an embodiment. It should be understoodthat the illustrations in FIGS. 4A and 4B are not intended to belimiting to the design of the fluidic system in any way, and are merelyprovided to demonstrate how reagent insert 402 can be used.

Reagent insert 402 may be shaped to snugly fit within a hole 404 on thebackside of housing 401, while hole 404 is aligned within testingchamber 210 on the front side of housing 401. Reagent insert may includea gasket seal around its edge to help prevent any fluid leaks after ithas been placed within hole 404. One side of reagent insert 402 mayinclude a variety of reagents to be used within testing chamber 210. Forexample, reagent insert 402 may include a surface having specificcapture antibodies to be used in an immunoassay. The reagents may befreeze dried upon a surface of reagent insert 402, or may be coated ontop of insert 402. Insert 402 may include a protective coating thatdissolves when in contact with fluid. According to one embodiment,reagent insert 402 may be removed from hole 404 at any time to bereplaced with a different reagent insert. Reagent insert 402 may besecured to the cartridge by means of any retention structure or adhesiveas would be understood by a person skilled in the art.

FIG. 5 illustrates another fluidic arrangement 500, according to anembodiment. A microfluidic channel 502 includes only one port 504 andcouples between chambers 506, which are arranged in series alongmicrofluidic channel 502. In one example, microfluidic channel 502follows a serpentine path with chambers 506 aligned horizontally alongthat path as illustrated in FIG. 5. Each individual chamber may bedefined as having a length longer than its width, with the lengthaligned substantially parallel with a gravity vector as shown.Additionally, the openings at the top and bottom of each of chambers 506are aligned with the gravity vector. According to an embodiment,microfluidic channel 502 terminates at an enclosed chamber 510. Enclosedchamber 510 may be designed as a reservoir for the air that is forcedthrough microfluidic channel 502 as liquid enters through port 504. Eachchamber of the plurality of chambers may have a fluid volume of lessthan 250 μl, less than 100 μl, or less than 50 μl.

Microfluidic channel 502 may also include a plurality of channelenlargements 508 a-508 e. Channel enlargements 508 a-508 e may act in asimilar way as previously discussed with reference to FIGS. 2 and 3.Channel enlargements 508 a-508 e may be arranged along microfluidicchannel 502 such that the number of chambers 506 between adjacentchannel enlargements is variable. In this context, adjacent channelenlargements describes any two channel enlargements that do not haveanother channel enlargement between them along the path of microfluidicchannel 502. In other words, an example pattern of channel enlargements508 (CE) and chambers 506 (CH) as fluid moves down microfluidic channel502 towards enclosed chamber 510 is: CE; CH; CE; CH; CH; CE; CH; CH; CH;CH; CE; CH; CH; CH; CH; CE.

According to an embodiment, fluidic arrangement 500 may be used forperforming dilutions, reagent dosings, or various mixing steps. Chambers506 may also be used to store various fluids for later use. For example,reagent solutions of different concentrations can be stored withinchambers 506 with a lowest concentration at the far left chamber andwith increasing concentrations for each chamber to the right until thehighest concentration in the far right chamber of chamber 506.Alternatively, a highest concentration may be in the far left chamber ofchambers 506, with decreasing concentrations for each chamber to theright until the lowest concentration in the far right chamber of chamber506.

In one example, a first liquid enters through port 504 up until itreaches channel enlargement 508 a. A liquid sensor is used at channelenlargement 508 a to determine the presence of the first liquid. Whenthe first liquid is determined to be at channel enlargement 508 a, asignal may be sent to stop flowing in the first liquid. Afterwards, asecond liquid is flown through port 504 until it reaches a differentchannel enlargement further downstream (any one of 508 b-508 e.) Thismay be repeated with other liquids following the second liquid. In thisway, known concentrations of two or more liquids may be stored withinchambers 506.

FIG. 6 is a flow chart illustrating a method 600 for using a fluidictesting arrangement, according to an embodiment. It should be understoodthat the steps shown in method 600 are not exhaustive and that othersteps may be performed as well without deviating from the scope orspirit of the invention.

At block 602, liquid is flown through a fluidic channel (e.g., via anapplied pressure) until it reaches reagents stored in a storage chamber,according to an embodiment. The liquid may enter the fluidic channelthrough a single port, which is the only input/output port of thefluidic channel. The reagents may be, for example, any dried reagents,freeze dried reagents, or reagents contained within a pellet to bedissolved by the liquid. This step may describe liquid moving throughmicrofluidic channel 202 until it reaches dried reagents 214 in storagechamber 212, as illustrated in FIG. 2.

At block 604, the reagents are re-suspended within the liquid. In oneexample, the liquid may be a buffer solution having properties thatallow for the reagents to be dissolved within the buffer and remainstable within the buffer. Once the reagents have been mostly dissolved,the liquid may be referred to as a target liquid for the remaining stepsof the process.

At block 606, the target liquid is flown away from the storage chamber.In the example illustrated in FIG. 2, the target liquid would be drawnback through the microfluidic channel and away from storage chamber 212.

At block 608, the target liquid is flown back and forth within thefluidic channel, such that it crosses through a testing chamber,according to an embodiment. This testing chamber may include another setof reagents that react with the re-suspended reagents in the targetliquid. The target liquid may be moved back and forth solely within thetesting chamber, or through other portions of the fluidic system aswell. For example, and with reference to FIG. 2, the target liquid maybe moved back and forth between channel enlargements 206 a and 206 b,such that the target liquid traverses both testing chamber 210 andmixing chamber 208. Passing the liquid multiple times through mixingchamber 208 may be an optional step to provide better mixing of there-suspended reagents within the target liquid. The liquid may also bemoved back and forth between channel enlargement 206 a and storagechamber 212.

At block 610, the reagents within the target liquid react with thereagents within the second chamber. This process occurs simultaneouslywith the movement of the liquid described above in block 608. In thecase of an immunoassay, capture antibodies or an antigen sample may beimmobilized in the second chamber while target antibodies/antigens bindto the capture antibodies/antigens. Other reactions may includeenzymatic reactions that result in a color (e.g., absorbance) change orreactions involving bioluminescent proteins.

At block 612, the target liquid is flown out of the fluidic channel bythe single port, according to an embodiment. The target liquid may beremoved via applying a negative pressure at the single port, thusdrawing the target liquid out. Following the removal of the targetliquid, other liquids may be introduced through the fluidic system. Forexample, various wash liquids may be introduced and flown through thesecond chamber to wash away any unbound material.

The foregoing description of the specific embodiments will so fullyreveal the general nature of the invention that others can, by applyingknowledge within the skill of the art, readily modify and/or adapt forvarious applications such specific embodiments, without undueexperimentation, without departing from the general concept of thepresent invention. Therefore, such adaptations and modifications areintended to be within the meaning and range of equivalents of thedisclosed embodiments, based on the teaching and guidance presentedherein. It is to be understood that the phraseology or terminologyherein is for the purpose of description and not of limitation, suchthat the terminology or phraseology of the present specification is tobe interpreted by the skilled artisan in light of the teachings andguidance.

Embodiments of the present invention have been described above with theaid of functional building blocks illustrating the implementation ofspecified functions and relationships thereof. The boundaries of thesefunctional building blocks have been arbitrarily defined herein for theconvenience of the description. Alternate boundaries can be defined solong as the specified functions and relationships thereof areappropriately performed.

The Summary and Abstract sections may set forth one or more but not allexemplary embodiments of the present invention as contemplated by theinventor(s), and thus, are not intended to limit the present inventionand the appended claims in any way.

The breadth and scope of the present invention should not be limited byany of the above-described exemplary embodiments, but should be definedonly in accordance with the following claims and their equivalents.

What is claimed is:
 1. A method comprising: flowing a liquid through anonly port of a fluidic channel until the liquid reaches one or morereagents stored in a first chamber coupled to the fluidic channel;re-suspending at least a portion of the one or more reagents within theliquid to form a target liquid; flowing the target liquid through thefluidic channel and away from the first chamber; flowing the targetliquid back and forth within the fluidic channel, such that the targetliquid flows through a second chamber coupled to the fluidic channel;reacting at least a portion of the one or more re-suspended reagentswithin the target liquid with one or more reagents disposed within thesecond chamber; and flowing the target liquid out of the fluidic channelvia the only port of the fluidic channel.
 2. The method of claim 1,wherein each opening to the second chamber is aligned substantiallyparallel to a gravity vector.
 3. The method of claim 1, wherein flowingthe target liquid back and forth within the fluidic channel comprisesflowing the target liquid back and forth between two locations of thefluidic channel.
 4. The method of claim 1, further comprising: sensing apresence of the liquid at each of the two locations of the fluidicchannel.
 5. The method of claim 1, wherein flowing the target liquidback and forth within the fluidic channel comprises flowing the targetliquid through a third chamber and mixing the target liquid as it flowsthrough the third chamber.
 6. The method of claim 1, further comprising:measuring an optical signal from the second chamber, wherein the opticalsignal is associated with a concentration of the one or morere-suspended reagents within the second chamber.
 7. The method of claim1, further comprising: flowing a second liquid through the only port ofthe fluidic channel; flowing the second liquid back and forth within thefluidic channel, such that the second liquid flows through the secondchamber; flowing the second liquid out of the fluidic channel via theonly port of the fluidic channel.
 8. The method of claim 7, wherein thesecond liquid is a wash buffer.
 9. The method of claim 1, wherein thereacting comprises binding at least a portion of the one or morere-suspended reagents within the target liquid with one or more reagentsdisposed within the second chamber.